It is known that protecting the health of people who work in closed environments, for example at home, in offices, hospitals, vehicles and aircraft of various kinds and other environments, is a considerably important requirement. These filtration devices must be fitted at the air outlets in ventilation and climate control systems and devices and the like for closed environments (civil environments, hospital environments and the like) and of means of transport (aircraft, trains, ships, military vehicles, even in spacecraft, and others), yet they are scarcely used and are not usually installed except in particular environments, such as for example a hospital environment, to suppress particles and in particular the microorganisms contained in the air, in order to preserve the health of people.
These microorganisms, i.e., biological pollutants such as viruses, bacteria, spores, molds, fungi and the like, are in fact, from a sanitary standpoint, the greatest danger for the health of people, since they can cause diseases and infections, in particular affecting the respiratory system.
Known types of filtration devices generally comprise partitions made of fabric, which are adapted to retain the particles and microorganisms that are present in the air that is made to pass through said partitions.
However, these devices have several drawbacks, since for example the filtration partitions must be cleaned or replaced rather frequently, and therefore they require frequent maintenance, which can be performed by specialized operators, with consequent high costs. Further, these partitions constrict the passage of the air and often, when the device is started, previously collected material may be introduced accidentally into the environment to be controlled, with consequent risks for the health of the people that are present. Moreover, some devices which comprise germicidal means based on UV rays with high emission power can generate gases that are noxious for the health of people, such as ozone, and are also ineffective against particular microorganisms which require, for their inactivation, long periods of exposure to UV rays.
EP-A1-0 644 379 discloses an air de-pollution device comprising a container having at opposite ends an intake grille and an emission grille. Closed inside the container are: filters arranged at the intake grille; a collection device arranged downstream of the filters; and suction means for creating a stream of air through the filters and the collection device, from the intake grille to the emission grille. The collection device comprises, in succession of the air stream flow: an electrification grid supplied with high negative polarity voltage for electrifying particles of the air stream passing therethrough; a pair of opposed plates, a first one of which is a negatively charged deflector plate and the second one of which is a positively charged collector plate; and a germicidal UV-ray neon lamp arranged for emitting light into the passage defined between the pair of opposed plates. The electrification grid electrifies (negatively charges) small particles in the air stream that are then repelled by the deflector plate toward the collector plate upon which they are collected and illuminated by the germicidal UV-ray lamp which thus kills the micro-organisms present in the particulate.